73 up control arm change over?

[mild68]

I have a 69 frame that appears to already have 73 up control arms w rubber bushings and disc brakes. I am restoring the suspension and plan on using the 73 up control arms. I also plan on getting a new front brake kit consisting of 73 up dropped spindles and HD rotor, caliper and components.

My question is about steering linkage. Tie rod ends and center link need to be from a 73 up? Correct?

Idler arm and pitman arm from the chassis year?

How can I tell what the power steering box is from? It appears to me that the frame may have came w power steering. has an indentation. Does it matter what year steering box?

One unrelated question if any one happens to know off hand. What is the part number for the rear control arms?

ready to move to the next stage
thanks